Rice is one of the most important crops in the world and it provides the main resource of energy for more than half of the world population. The estimated physical size of the rice genome is about 430 Mb, the smallest among all the cereal crops. It corresponds to one seventh of the human genome whose working draft has been established. It is also 3.5 times the size of Arabidopsis.The well-established protocols for relatively high-efficiency genetic transformation, the genetic and physical maps of high density, and the high degree of synteny among genes in cereal genomes, all make rice an ideal model organism for studies on physiology, developmental biology, molecular genetics, evolution, and genomics of plants, especially of the grass family. Essential biological information from the rice genome will undoubtedly improve our understanding of the basic genomics and genetics of other related and economically significant crops, not only wheat, corn, sorghum, and members of the grass family, but also dicot crops such as soybean and cotton.

The initiation of the Human Genome Project (HGP) at the beginning of the l990s and the completion of the human genome working drafts at the beginning of this century have not only laid the ground work for genomics and opened a new era for the life science research, but also have set up an unprecedented example for genomics studies on many other organisms. HGP has developed strategies, technologies, definitions and standards for different stages of sequence assembly and analysis such as "working draft", "draft sequences" and "complete map", which are broadly applicable to other organisms.

Inspired by the Human Genome Project, the International Rice Genome Project Consortium, headed by Japan, has released 174.4 Mb of BAC/PAC-based non-redundant sequences since 1997, including the complete sequence of a single chromosome (Chr. 1). Monsanto and Syngenta, two private companies, have announced the establishment of a "working draft", independently, in April of 2000 and February of 2001, respectively, but neither has made their sequence data completely available to the public. All of the three projects mentioned above have used subspecies japanica (Nipponbare) as target materials, in spite of the fact that another subspecies, indica, is dominantly planted in Asia and other regions in the world, and has provided the unique template for the unique hybrid rice strain that has greatly contributed to solving the food supply problem in China.

Beijing Genomics Institute (BGI), the major genome sequencing center in China, has been carrying out the Superhybrid Rice Genome Project (SRGP) with full efforts to understand genome biology of the rice. In BGI-RIS, we report the latest progress in the assembly and annotation of the rice genome of 93-11, a cultivar of Oryza sativa ssp. indica and the major food crop in China, and present the sequenced genomes and related information in systematic and graphical ways, which further lay the foundation for the in-depth comparative studies between rice subspecies.